Date information recorded within a conforming METS document aside from elements within the MARC XML Schema must conform to ISO 8601 format.
All information recorded within the portion of a conforming METS document defined using the MARC XML Schema must employ ISO 639-2 language codes within the controlfield[@tag=008] element.
ISO language codes.
All information recorded within the portion of a conforming METS document defined using the MARC XML Schema must employ MARC Country codes within the datafield[@tag=043] element.
MARC Country codes.
The ID attribute in the metsHdr element must be present. It will contain the namespace and identifier for the item, separated by a period (e.g., uc1.b3387194). This value must match the OBJID attribute on the mets root element.
A conforming metsHdr will contain an agent element identifying the creator of the METS document (as opposed to the creator of the electronic files it describes).
A conforming METS document must contain at least one dmdSec with an ID of "DMD1" containing a mdRef to an item ID stored as second call number in item record and an XPTR with the value of the metsHdr ID. This must be the first dmdSec in a conforming METS document.
A conforming METS document may contain a second dmdSec with an ID of "DMD2" containing an MDWrap with MARC XML.
A conforming METS document must contain a techMD element with an MDWrap containing the PREMIS preservationLevel element and digiprovMD element with an MDWrap containing all relevant PREMIS events and associated metadata as specified in the PREMIS Data Dictionary version 1.0 (http://www.loc.gov/standards/premis/).
A conforming METS document will contain at least three file groups as follows:
The first file group, for the zip archive, must have an ID of "FG1" and a USE of "zip archive". It must contain one file element. The file element will contain the following attributes: ID, MIMETYPE, SEQ, CREATED, SIZE, CHECKSUM, CHECKSUMTYPE. The file element will contain an FLocat subelement with an xlink:href to the file described.
The second file group, for page images (bitonal and continuous tone), must have an ID of "FG2" and a USE of "image". It will contain a file element for each image. The file elements will contain the following attributes: ID, MIMETYPE, SEQ, CREATED, SIZE, CHECKSUM, CHECKSUMTYPE. Each file element will contain an FLocat subelement with an xlink:href to the file described.
The third file group, for OCR text files, must have an ID of "FG3" and a USE of "OCR". It will contain a file element for each page of OCR. The file elements will contain the following attributes: ID, MIMETYPE, SEQ, CREATED, SIZE, CHECKSUM, CHECKSUMTYPE. Each file element will contain an FLocat subelement with an xlink:href to the file described.
A conforming METS document may contain a fourth file group for hOCR files. If included, it must have an ID of "FG4" and a USE of "coordOCR". It will contain a file element for each page of OCR. The file elements will contain the following attributes: ID, MIMETYPE, SEQ, CREATED, SIZE, CHECKSUM, CHECKSUMTYPE. Each file element will contain an FLocat subelement with an xlink:href to the file described.
These file groups must be in the order listed.
A conforming METS document must contain only one structural map with a type value of "physical". There must be a div element for the volume within the structural map which will contain a div for each page. Each div must have a ORDER attribute, a TYPE attribute of "page" and contain an fptr to the matching page image file and to all matching OCR or hOCR files. In addition, page divs may contain LABEL and ORDERLABEL attributes, as appropriate.
A conforming METS document must not contain a structLink element.
A conforming METS document must not contain a behaviorSec element.
All bitonal images referenced by a conforming METS document must be in TIFF format and must be well-formed and valid. The MIME type must be image/tiff. The compression scheme must be CCITT Group 4. Bits per sample must be “1”.
All bitonal images must be accompanied by an XMP packet. It must contain the following elements from the tiff namespace: PlanarConfiguration, ImageWidth and ImageLength (must match the ImageWidth and ImageLength values from the header), BitsPerSample (must be 1), Compression (must be 4), PhotometricInterpretation (must be 0), Orientation (must be 1), SamplesPerPixel (must be 1), XResolution and YResolution (must be 600/1 for Google-scanned materials), ResolutionUnit (must be 2), DateTime, Artist, Make, and Model. It must contain the following element from the Dublin Core namespace: source (must contain “barcode/filename”).
All continuous-tone images referenced by a conforming METS document must be in JPEG2000 format and must be well-formed and valid. The MIME type must be image/jp2. The compression scheme must be JPEG2000. The JPEG2000 metadata must be of the brand jp2, minor version 0, and compatibility jp2. The number of layers must be 8. The color specification EnumCS must be sRGB or Greyscale. Bits per sample value is “8, 8, 8” if EnumCS is “sRGB”; value is “8” if EnumCS is “Greyscale”. The number of decomposition levels must be a value between 5 and 32, inclusive. XSize and YSize must be present in the header.
All continuous-tone images must be accompanied by an XMP packet. An x-packet declaration with a 'begin' attribute must be present and the 'id' attribute must be W5M0MpCehiHzreSzNTczkc9d. It must contain the following elements from the tiff namespace: ImageWidth and ImageLength (must match the XSize and YSize values from the header), BitsPerSample, Compression (value must be “34712”), PhotometricInterpretation (value is “2” if EnumCS is “sRGB”; value is “1” if EnumCS is “Greyscale”), Orientation (must be 1), SamplesPerPixel (value is “1” if EnumCS is “Greyscale”; value is “3” if EnumCS is “sRGB”), XResolution and YResolution (must be 300/1 for Google-scanned materials), ResolutionUnit (must be 2), DateTime, Artist, Make, and Model. It must contain the following element from the Dublin Core namespace: source (must contain “barcode/filename”). An x-packet declaration with an end attribute must be present.
All OCR text files must be well-formed and valid UTF-8 with a MIME type of text/plain.
All hOCR HTML files must be well-formed and valid UTF-8 with a MIME type of text/html.
There must not be any behaviors associated with a conforming document.
The HathiTrust pageturner is a public application that makes use of the HathiTrust METS document. Access to the digital objects (page images and OCR) is controlled solely by application logic. More information is available at http://www.hathitrust.org/pageturner .
TheHathiTrust Data API is a RESTful API to provide access to HathiTrust repository data and metadata resources. More information is available at http://www.hathitrust.org/data_api .